Hash and bools

During the discussion of bools and hash index and partial indexes and 
index growth and everything else, I tried to make a partial index on a 
bool field and got the error that "data type bool has no default operator 
for class hash..."

So, can I cast something to make this work, or is it possible to make 
hash indexes work with bools.  There are a few instances where a small 
percentage of a table is marked false while the rest is true, or vice 
versa, where a partial hash index would be nice to try, and may not have 
the ever expanding index problem that brtees have.

-- 
"Force has no place where there is need of skill.", "Haste in every 
business brings failures.", "This is the bitterest pain among men, to have 
much knowledge but no power." -- Herodotus